<script>
    function MadeCat(name, age) {
        // this指向了谁?this指向了MadeCat的实例,因为this.__proto__ === MadeCat.prototype 为true, 
        // 实例.__proto__ === MadeCat.prototype也是true, 说明this跟实例是同一个对象
        console.log(this);
        debugger;
        this.name = name;
        this.age = age;
    }
    var cat = new MadeCat('小白', 2);
</script>